EFFECT OF LEAF-TO-FRUIT RATIO AND GIRDLING ON GAS EXCHANGES, FRUIT GROWTH AND CARBOHYDRATE CONTENTS AT DIFFERENT STAGES OF FRUIT DEVELOPMENT OF OLEA EUROPAEA L. 'PICHOLINE'

The effects of different source-sink ratios on fruit quality were studied for the table olive cultivar ‘Picholine’. This cultivar represents 15% of the production of table olives in Tunisia. Fruit size is an important quality parameter for table olives as small fruits have lower economical value. Three tertiary branches/tree were selected on 27-years-old olive trees (10 trees in total) at the start of the growing season 2009. After fruit set in early May four fruit-to-leaf ratios were imposed on 1-year-old wood (no fruits, 1:1, 1:2, 1:3) of each branch. Apexes of all shoots were removed in order to reduce the vegetative sinks. In mid-July five trees were randomly selected and all branches were girdled. The absence of fruits or girdling decreased leaf net photo-synthetic rate (A_n) and increased leaf carbohydrate contents. Girdling stimulated fruit growth, while the effect of leaf-to-fruit ratio was less pronounced.